1. Field of the Invention
The present invention relates to a source separation, and more particularly, to a method of and an apparatus for eliminating cross-channel interference, and a multi-channel source separation method and a multi-channel source separation apparatus using the same.
2. Description of Related Art
A source signal separation has been increasingly used in a variety of fields such as communication systems, a biological signal processing, and a speech signal processing. Blind source separation (BSS) refers to a method of separating an original source signal by using a difference between input signals of each microphone without a priori knowledge of those signals when mixtures of input signals are input to a plurality of microphones. A typical BSS method shows a satisfactory performance in an ideal environment simulated in a laboratory, but performs poorly in a real environment. This is because the BSS method postulates limiting the length of filtering due to use of a convolutive mixing filter as a linear finite impulse response filter. Unfortunately, real signals do not follow such a postulation because non-linear electrical noises can be added or the sound sources can be moved during collecting the microphone signals.
In order to solve such a problem, a spectral subtraction has been used as a post-processing for eliminating remaining crosstalk signals that have not been completely eliminated by a conventional BBS method. Spectral subtraction is advantageous in that inconsistency between a real filter and an estimated filter can be effectively eliminated, so that a clear signal without noises or interference can be generated. However, a musical noise still remains due to spectral components below zero.
Recently, there have been several documents disclosing the BSS method, such as U.S. Pat. No. 6,167,417. Also, documents relating to a post-processing after the BSS have been disclosed in, for example, “Application of blind source separation in speech processing for combined interference removal and robust speaker detection using a two-microphone setup” (USCD & Softmax, in Proceedings of ICA2003, pages 325-329) by Erik Visser and Te-Won Lee, and “Robust real-time blind source separation for moving speakers in a room” (NTT Corporation, Kyoto, Japan, in Proceedings of ICASSP2003, Vol. V, pages 469-472) by Ryo Mukai et. al.